PCMO metal oxide is very hard to etch by a dry etch process. PCMO etching has been reported to include use of chlorine and argon, however, the etch rate is too low for commercial applications, and the masks used in the processes are unstable, and do not remain intact. It is also reported that PCMO has been sputter etched using pure argon, however, many of the same problems arise, in that selectivity of the etch of the PCMO thin film is poor when compared to the mask material and any underlying layers. Lee et al., Dry Etching to Form Submicron Features in CMR Oxides: PrBaCaMnO3 and LaSr MnO3, which is available at mse.ufl.edu/˜spear/recent_papers/cmr_oxides/cmr_oxides.pdf.